Drier felt



April 1, 1941. J. R. L. SANTOS DRIER FELT Filed May 16, 1939 2Shets-Sheet l mm J'oh 11R InSgnf'os Ap 1, 1941. J. R. SANTOS DRIER FELTFiled'llay 16, 1939 2 Sheets-Sheet 2 (73511 R L/Sdni'og Patented Apr. 1,194i DRIER FELT John R. L. Santos, Baltimore, Md., assignor to WilliamE.

Hooper & Sons Company, Baltimore,

MIL, a corporation of Maryland Application May 16, 1939, Serial No.273,935 3 Claims. (01. 139-415) The invention relates to a fabric foruse as a drier felt primarily for paper making machines but also capableof use on laundry ironers and other machines requiring such a felt.

In the paper making art to which the drier felt of the invention isapplied, the paper pulp, after being distributed and partially drainedis dried by passing it, while on the felt, in contact with heated drums,the pulp passing between the drums and the felt; and the laundry ironingoperation to which the drier felt may be applied is similar in that thefabric to be ironedis carried by the drier felt in contact with heateddrums. The water and acid from the pulp mixture and likewise the waterand some of the solvent from the fabrics treated in laundry ironingmachines, are driven off as vapors and the greater portion of this vapormust escape by penetrating and passing through the felt.

Among the important features of a satisfactory drier felt are (1) adegree of permeability sufiicient to insure eflicient drying (2) tensilestrength suflicient to prevent stretching or breaking (3) asmooth'surface which is presented to and serves to support the paperpulp or web (4) resistance to acids and heat.

Resistance to acids and heat is obtainable without special fibers tomeet the average conditions in paper making. However, increasedresistance to acids and heat are desirable under certain conditions.This increased resistance may be attained by the use of mineral yarnsuch as asbestos and the present invention includes as one of its ofsecondary importance features a combination of asbestos and cotton whichis highly efficient in its resistance to heat and excessive acidconditions.

To meet the conditions presented in the treatmen-t of paper pulp and inthe drying of other materials which can be handled in this way by meansof a drier felt passing the material in contact with the heated drums,the felt of the invention has a smooth surface which is presented to andsupports the paper. The drier felt of the invention is also highlypermeable and thus insures satisfactory drying; it further possesses ahigh degree of tensile strength in proportion to the weight of thefabric and the expense involved in producing it.

In the past drier felts have been made of two or more layers but it isfound that the majority of multiple layer fabrics which present a smoothsurface to the pulp are relatively impermeable and therefore not adaptedto drying. and that such fabrics are of complicated weaves andrelatively heavy. Such fabrics are expensive on account of theircomplicated construction and their excess weight.

The drier felt of the invention has the advantages first of a highdegree of tensile strength in proportion to its weight, second, that theface of the felt formed by one of the plies or layers is specially wovenfor presenting the required smooth surface to support the pulp orsimilar material, third, that the second layer is of an open weaveconstituting the back of the drier felt and providing for the escape ofvapors which have passed through the first layer and are thus releasedwith very little additional resistance, and, fourth, the fabric is of arelatively low cost because of its simple weave, light weight inproportion to its tensile strength and resistance to absorption.

The fabric of the invention, as above suggested, has a central core warpwith two layers or piles of filling, the terms layer and ply being usedinterchangeably. One layer of filling is above the core warp and theother below, and the top layer of the filling contains twice as manyfillings as the bottom layer and there is an additional warp, and thefillings of the top layer are interwoven by and with this latter warpwhich is not interwoven with the bottom layer.

While an alternative construction of cotton in combination with asbestosis disclosed for use where asbestos is found desirable, the proportionof mineral yarns may be further in creased if it is found essential onaccount of intensely acid conditions but in the majority ofinstallations the use of such special fibers is unnecessary, the feltbeing made of cotton or similar vegetable fibers.

In the accompanying drawings, I have illustrated a drier felt fabricmade of cotton or similar fiber in accordance with my invention, alsothe drier felt fabric of the same construction composed in part ofcotton yarn and in part of asbestos yarn combined and arranged inaccordance with the feature of my invention which relates to thiscombination of material.

In the drawings:

Fig. 1 is a longitudinal section through the fabric on the line l-l inFig. 2, looking in the direction of the arrow.

Fig. 2 is'a top plan viewof the same, the warp and filling beingseparated or spaced apart for convenience of illustration.

Fig. 3 is a section similar to Fig. 1, taken on the line 3-3 in Fig. 4,showing a fabric having an asbestos warp, a cotton core, and a cottonfilling.

Fig. 4 is a top plan view of the same, the warp and weft thread beingspaced apart for convenience of illustration. Figsl 2 and 4 beingdiagrammatic in nature.

Referring to the drawings by numerals, each of which is used to indicatethe same or similar parts in the different figures, the fabric shown inFig. 1 comprises a core or stuffer warp I, and in the fabric shown,there is one core warp in every four warp threads comprising a set ofbinder warp threads, such sets being repeated an indefinite number oftimes in the fabric. The other warp threads in the set shown in Fig. 1comprise the warp thread 2, which is at the bottom in Fig. 2 and closestto the observer in Fig.

1. This warp 2 passes over every fourth top weft or filling 3 in the toplayer 8, as seen in Figs. 1 and 2, so that there are three top wefts .orfillings l, 5, and 6, between each filling 3,

the wefts or filling threads 3, 4, 5 and 6 comprise a set of top weftswhich is indefinitely repeated, the warp thread 2 also passes underevery alternate weft or filling I in the bottom layer. It is ofimportance that there are but half as many wefts or fillings in thebottom layer as in the top layer, the wefts or filling threads of whichbottom layer l3 are in sets of twos indicated by reference characters Iand H, such sets being indefinitely repeated. The bottom wefts orfillings l and II are directly beneath the wefts or fillings 5 and 3respectively of the set 3, l, 5, and 6 of the top layer. A second warpII is arranged similarly to the warp 2, except that it passes over everyfourth weft or filling 5 of the top layer and under every alternate weftor filling ll of the bottom layer. Thetop layer 8 differs from thebottom layer l3 in that it contains two additional fillings l and 6, ineach set between the fillings 3-5 and 5-3 respectively and, the toplayer further differs from the bottom layer in that each set of warpscontains a surface warp l2 the third from the front in Fig. l and fromthe bottom in Fig. 2, whichwarp I! in the form shown passes alternatelyover and under the wefts or filling threads 3, 4, 5 and 6 of the toplayer, but does not cross to the bottom layer.

This construction provides a relatively smooth surface 8" to support thepaper or other material being treated and at the same time the highpermeability of the bottom layer permits the steam and acid vapors to bedischarged with great freedom giving quick and satisfactory drying. Thefabric also possesses high tensile strength and high resistance toelongation in proportion to its weight. This feature and the simplenature of the weave greatly reduce the cost as compared to the priorfabrics for the same installations.

A highly satisfactory arrangement of asbestos or similar fiber to reduceand prevent deterioration on account of conditions of increased acidityencountered in some classes of paper making the asbestos being used incombination with sufficient cotton to give the desired tensile strengthand keep the cost at a satisfactory figure is illustrated in Figs. 3 and4. In the construction shown in these figures, the core warp l is ofcotton, likewise the warp l2 which is interwoven above and below thefillings 3', 4', 5' and 6' of the top layer, and assists in giving asmooth top surface which supports the paper pulp or other material to bedried. The remaining warps 2' and III, in the form shown in thesefigures are of asbestos and being the warps which are most exposed,particularly, those passed over and under the alternate fillings 8, l'and 5', ll? of both the top and bottom layers serve to protect the coreI and to preserve the construction of the fabric and give it strengthand body even when the cotton is attacked by acid which may happen underexcessively acid conditions. This fabric is otherwise similar to that ofFigs. 1 and 2. I

It is of interest that the fabric disclosed except for the extrafillings l, 6, and the additional warp It, all being confined to the toplayer, is a two layer, interwoven by three separate warp threads fabric.The extra fillings l and 8 between each of the fillings 3 and 5 and theaddition of the warp l2 interwoven with all the fillings of the toplayer give a smooth top supporting surface adapted to support the paperpulp or web, and the relatively open bottom layer provides an easilypermeable back. This construction with the longitudinal core also givesa weave in which the strength of the fabric in proportion to its weightand its resistance to elongation are greatly increased withoutappreciably decreasing the permeability of the fabric.

Under certain circumstances, as already pointed out, the proportion ofasbestos may, if desired, be increased in correspondence with increasedacidity, even to the extent of all of the warp and filling yarns beingmade of asbestos. Under ordinary conditions, the cotton fabric servesthe purpose to such a high degre oi satisfaction as tomake the expenseof other fibers the specific terms herein are used in a descrip-' tivesense, the scope of the invention being "deunwarranted.

Having thus described a preferred and modified form of the invention,one to meet standard conditions, and the other to meet conditions ofincreased acidity, I would have it understood that fined in the claims.

What I claim as new and desire to secure by Letters Patent is:

.1. A drier felt having two layers of filling comprising a top layerhaving closely spaced filling threads, a bottom layer consisting offillings in number equal to one filling thread for each two fillingthreads of the top layer, two sets of warp threads by which thealternate fillings of the top layer are interwoven with all the fillingsof the bottomlayer, an additional set of warp threads interwoven withand passing alternately over and under all the consecutive top fillingthreads and being free of the bottom layer, and

a set of core warp threads passing between the fillings of the top layerand the fillings of the bottom layer'.

2. A drier felt fabric comprising a core of stufler warp threads, a toplayer of filling threads on one side of said core of stuffer warpthreads and a relatively open bottom layer of filling threads on theother side of the core warp threads, the top layer consisting of twofilling threads for each filling thread of the bottom layer and two setsof binder warp threads by which alternate top filling threads and all ofthe bottom filling threads are interwoven, leaving the top remainingintervening filling threads not interwoven with said latter sets of warpthreads and an additional set of surface warp threads interwoven withall of the top layer of filling threads whereby all the filling threadsare interwoven into the fabric, the warp threads of said latter setpassing over the intervening filling threads of the top layer which arenot interwoven with said warp threads which interweave the top andbottom layers.

bottom filling threads are interwoven, leaving the top remainingintervening filling threads not interwoven with said latter sets of warpthreads and an additional set of surface warp threads 5 interwoven withall of the top layer of filling threads whereby all the fillingthreadsare in- -terwoven into the fabric, the warp threads of said latter setpassing over the intervening filling threads of the top layer which arenot inter 10 woven with said warp threads which interweave the top andbottom layers, there being one stuifer warp thread and one surface warpthread and two binder warp threads in each warp repeat,

JOHN R. L. SANTOS.

